Draft gear



Feb. 10, 1942. R. CFPIERCE DRAFT GEAR Filed May 14, 1940 v @VwRd ww,

Patented Feb. 10, 1942 ATENT OFFICE 18 Claims.

My invention relates to friction absorbing mechanisms for railway cars and more particularly to a draft gear of the barrel type wherein the mechanism consists of an outer housing of generally cylindrical form with compression springs enclosed therein and an outwardly flaring open end wherein is received what is sometimes known as a clutch mechanism.

My invention contemplates an improved type of such a mechanism as disclosed in United States Letters Patent 2,205,066, issued June- 18, 1940, in the name of Raymond C. Pierce and Edmund P. Kinne. The draft gear disclosed in said patent comprises generally a barrel type housing having a plurality of friction shoes urged outwardly into engagement therewith by the wedging action of inner and outer followers on insert members engaging said friction shoes along relatively sharp angles and wherein the shoes are afforded flat face engagement with the inner follower along a plane at right angles to the axis of the ear. My present invention contemplates an improved modification of said draft gear wherein greater frictional absorption is developed by the clutch mechanism.

It is an object of my invention to design such a draft gear wherein the engagement of the bottom surfaces of said shoes with the inner follower may be along surfaces other than the flat surface engagement above described.

A further object of my invention is to design a modification of such a, draft gear wherein the inner surfaces of said shoes engage the inner follower along faces lying in planes inclined to the longitudinal axis of said gear.

My invention also contemplates such a draft gear wherein the engagement between the shoes and the inner follower may be along diagonally arranged arcuate faces.

Referring to the drawing, Figure 1 is a fragmentary sectional view of a draft gear embodying my invention, the section being taken substantially in a plane bisecting the gear longitudinally as indicated by the line ll of Figure 2.

Figure 2 is an end elevation, partly in section, the ection at the lower portion of the figure being taken in the transverse Plane substantially as indicated by the line 2--2 of Figure 1, and the section at the upper left of the figure being taken substantially in the transverse plane indicated by line AA of Figure 1. I

Figure 3 is a plan view of the combination spring cap and inner follower, the View being taken from the outer face thereof. Figure 4 is a side elevation of said inner follower.

Figure 5 is a fragmentary sectional view showing one modification of the friction shoe engaging surface on the inner follower, the section being taken substantially in the plane indicated by line 5-5 of Figure 4.

Figure 6 is a plan View of one of the friction shoes, the view being taken from the inner face thereof. Figure 7 is an end elevation of the shoe, the view being taken from the outer end. Figure 8 i a sectional view of the shoe taken substantially in the plane bisecting said shoe as indicated by line 8-8 of Figure 6. V

Figure 9 is a fragmentary sectional view showing the engagement of the shoe and inner follower, the section being taken substantially in the plane indicated by line 9-9 of Figure 1.

Figures 10, 11, and 12 show a different modification of the face engagement between each shoe and the inner follower wedge, Figure 10 being a fragmentary sectional view taken in substantially the same plane as that in Figure 9, Figure 11 being a fragmentary sectional view taken substantially in the same plane as that in Figure 5, and Figure 12 being a fragmentary sectional view taken in a plane substantially at right angles to the inner follower engaging face on the friction shoe.

Describing my invention in greater detail, the general y cylindrical housing 2 is of a form more particularly described and shown in United States Letters Patent No. 2,160,417, issued May 30, 1939, in the name of William C. Hedgcock. Enclosed within said housing are the outer and inner compression springs 4 and 6, said springs being positioned at their inner ends on the base of said housing (not shown), and at their outer ends, said springs may be seated as at 8 and Ill against the combination spring cap and inner follower wedge 12. The inner surface of said follower wedge may be centrally recessed as at l4 to position the inner coil spring 6.

A plurality of friction shoes l6, it may be symmetrically arranged within the open end of said housing and seated against the inwardly tapering internal V-shaped friction surfaces I8, 18 formed on said housing. The inserts 2'0, 20 may be interposed between the respective shoes 16, I6 and the outer follower 22, said inserts being of a form more particularly described in said first-mentioned patent. Each insert 20 may have diagonal shallow cylindrical face engagement as at 21 with an adjacent shoe [6 and diagonal flat face engagement as at 23 with the outer follower 22 as best seen in the lower portion of Figure 2. The inner end of each insert frictionally engages as at a diagonally arranged surface 40 on the outer end of the central boss 24 formed on the inner follower wedge l2. It will be noted that the diagonal face engagement of the inserts 20, 20 with the follower wedges l2 and 22 and the shoes l6, l6 transmit thrust in such manner that the shoes are urged outwardly against the housing.

The outer follower 22 may be of cup-like form having on its inner portion spaced diagonally arranged faces for complementary engagement with the inserts 2B, 20 as at 23. The flat outer surface 26 may have abutment with an associated conventional follower block. The bolt 21 serves to retain said draft gear in assembly.

As best shown in Figures 1 and 9, interrupting the bottom surface of each shoe [6 maybe a groove 28 which receives a complementary tongue or slightly raised portion 30 on the inner follower wedge [2 to interlock said shoes with said inner follower in such manner that relative rotation therebetween is substantially prevented. On opposite sides of each tongue 30, diagonally arranged surfaces 32, 32 on the inner follower wedge engage as at 36 complementary faces 34,

34 formed on opposite sides of the groove 28 on the diagonal arrangement of the surfaces 32, 32

disposed on opposite sides of each tongue 36. Briefly, the base 38 is of general hexagonal shape having on its inner surface the aforedescribed central positioning recess 14. The central boss 24 affords on its outer face three diagonally arranged fiat faces 40, 40 for engagement with the inserts 2D, 20, said faces being aligned with the surfaces 32, 32. The central hole 42 receives the retaining bolt 21,

The detailed structure of each friction shoe [6 is shown in Figures 6, 7, and 8. Each friction shoe l6 corresponds generally to that disclosed in the said first mentioned patent and differs therefrom in the particular diagonal arrangement of the faces 34, 34 disposed on opposite sides of the groove 28. On the bottom face of each shoe said faces 34, 34 slope upwardly and inwardly and are complementary to the friction surfaces 32', 32 formed on the inner wedge follower l2. Briefly, each shoe is V-shaped in crosssection and of slightly greater width at its outer end than at its inner end to accommodate the shoe in the flaring open end of the housing 2. The generally V-shaped outer face 44 is complementary to the friction surface 3 formed within said housing 2. On its inner face each shoe has a cylindrical surface 46 defining a relatively shallow cavity designed to accommodate complementary surface formed on the outer face of each insert 20.

A different modification of the engagement of said shoes l5, IS with the inner follower wedge I2 is shown in Figures 10, 11, and 12. In this modification, it will be noted that each shoe I6 engages the inner follower wedge [2 along inclined and slightly arcuate faces as at 48. Each face 50 formed on opposite sides of the tongue 30 on the inner follower wedge l2 slopes upwardly similarly as in the previously described modification and may be of slightly arcuate form as best seen in Figures 10 and 11. Each shoe I6 has surfaces 52, 52 (Figure 12) complementary to said faces 50, 50. It should be noted that said arcuate face engagement tends to stabilize and steady each shoe l6 during operation of the draft gear.

In operation as impact is received against the outer follower 22', the clutch mechanism is forced into the housing and the shoes l6, l6 are urged inwardly because of the tapering internal surfaces l8, IS. The inserts 2D, 20 are squeezed between the followers and the shoes, and resistance to the inward movement of said shoes is afforded by the main friction faces 44. 44 of the shoes engaging the housing and by the diagonally arranged face engagement of the inserts with the followers and the shoes as well as by the diagonal face engagement of the bottom faces on said shoes with the inner follower wedge. When the load is released, the outer follower wedge promptly frees itself from the inserts because of the relatively flat angles between said outer follower and said inserts. The other parts of the clutch mechanism are then free to return to their normal released positions.

It is to be understood that I do not wish to be limited by the exact embodiments of the device shown which are merely by way of illustration and not limitation as various and other forms of the device will, of course, be apparent to those skilled in the art without departing from the spirit of the invention or the scope of the claims.

I claim:

1. In a friction absorbing device, a housing having an open end, a compression spring, and a clutch mechanism seated in said open end, said mechanism comprising inner and outer wedges, said inner wedge being seated against said spring, a plurality of symmetrically arranged friction shoes and thrust means associated with each shoe, said thrust means having diagonal cylindrical face engagement with the associated shoe and diagonal face engagement with each of said wedges, said inner wedge having tapering surfaces engaging complementary faces on each of said shoes, and means on one of said wedges interlocking with each of said shoes to prevent relative rotation thereof.

2. In a draft gear, a housing having an open friction end, a compression spring, a clutch means seated on said friction end and comprising a plurality of shoes seated around said friction end, an inner wedge follower seated against said spring, an outer wedge follower, independent thrust means extending between said wedge followers and in abutment with said shoes respectively, engaging means on each of said shoes and on one of said followers to limit relative rotation thereof, each of said shoes also having thrust engagement with said last-mentioned follower along diagonally disposed surfaces on opposite sides of said engaging means.

3. In a draft gear, a housing having an open friction end, a compression spring, a clutch means seated on said friction end and comprising a plurality of shoes seated around said friction end, inner and outer wedge followers, said inner wedge being seated against said spring, independent thrust means extending between said wedge followers and in abutment with said shoes respectively, engaging means on each of said shoes and on one of said followers to limit relative rotation thereof, each of said shoes also having thrust engagement with said last-mentioned follower along shallow diagonal cylindrical surfaces on opposite sides of said engaging means.

4. In a draft gear of barrel type, a housing having an open end with tapering friction surfaces symmetrically arranged there-around, a compression spring, and clutch mechanism comprising a plurality of shoes seated against said friction surfaces, an inner wedge follower abutting said spring, an outer wedge follower, and a thrust member extending between said followers for each shoe and transmitting thrusts from said followers to said shoe, each of said shoes also having thrust engagement with one of said followers on a plurality of spaced areas along surfaces lying in planes inclined to the longitudinal axis of said gear.

5. In a friction absorbing device, a housing having an open end, a compression spring, and a clutch mechanism seated in said open end, said mechanism comprising inner and outer wedges, said inner wedge being seated against said spring, a plurality of symmetrically arranged friction shoes, and thrust means associated with each shoe, said thrust means having diagonal cylindrical face engagement with the associated shoe and diagonal fiat face engagement with each of said wedges, each of said shoes having thrust engagement with one of said wedges along a plurality of spaced diagonally arranged surfaces.

6. In a friction absorbing device, a housing having an open end, a compression spring, and a clutch mechanism seated in said open end, said mechanism comprising inner and outer wedges, said inner wedge being seated against said spring, a plurality of symmetrically arranged friction shoes, and thrust means associated with each shoe, said thrust means having diagonal cylindrical face engagement with the associated shoe and diagonal flat face engagement with each of said wedges, one of said wedges having diagonal arcuate face engagement with each of said shoes along a plurality of spaced areas.

7. In a friction absorbing device, a housing having an open end, a compression spring, and a clutch mechanism seated in said open end, said mechanism comprising inner and outer wedges, said inner wedge being seated against said spring, a plurality of symmetrically arranged friction shoes, and thrust means associated with each shoe, said thrust means having diagonal cylindrical face engagement with the associated shoe and diagonal flat face engagement with each of said wedges, one of said 'wedges having diagonal cylindrical face engagement with each of said shoes at the bottom thereof.

8. In a friction absorbing device, a housing having an open end, a compression spring, and a clutch mechanism seated in said open end, said mechanism comprising inner and outer wedges, said inner wedge being seated against said spring, a plurality of symmetrically arranged friction shoes and thrust means associated with each shoe, said thrust means having diagonal cylindrical face engagement with the associated shoe and diagonal face engagement With each of said wedges, said inner wedge having diagonally arranged arcuate surfaces engaging complementary faces on each of said shoes.

9. In a draft gear, a barrel having a friction end, a compression spring therein, and clutch mechanism comp-rising shoes symmetrically seated around said end, inner and outer follower wedges, said inner wedge being seated against said spring thrust members extending between said wedges for transmitting thrust therefrom to said shoes respectively, the engaging surfaces between said thrust members and said shoes being of diagonal cylindrical form, said inner wedge having diagonal engagement with each shoealong surfaces lying in planes inclined to the longitudinal axis of said gear.

10. In a draft gear, a barrel having a friction end, a compression spring therein, and clutch mechanism comprising shoes symmetrically seated around said end, inner and outer follower wedges, said inner wedge being seated against said spring, thrust members extending between said wedges for transmitting thrust therefrom to said shoes respectively, the engaging surfaces between said thrust members and said shoes being of diagonal cylindrical form, one of said wedges having spaced inclined surfaces engaging complementary faces on the bottom portion of each shoe.

11. In a draft gear, a barrel having a friction end, a compression spring therein, and clutch mechanism comprising shoes symmetrically seated around said end, inner and outer follower wedges, said inner wedge being seated against said spring, thrust members extending between said wedges for transmitting thrust therefrom to said shoes respectively, the engaging surfaces between said thrust members and said shoes being of diagonal cylindrical form, one of said wedges having spaced diagonal arcuate surfaces engaging complementary faces on the bottom portion of each shoe.

12. In a draft gear of barrel type, a housing having an open end with tapering friction surfaces symmetrically arranged therearound, a compression spring, and clutch mechanism comprising a plurality of shoes seated against said friction surfaces, an inner wedge follower positioned on said spring, an outer wedge follower and a thrust member extending between said followers foreach shoe and transmitting thrusts from said followers to said shoe, each of said shoes also having thrust engagement with one of said followers on a plurality of spaced areas along diagonally arranged surfaces.

13. In a draft gear of barrel type, a housing having an open end with tapering friction surfaces symmetrically arranged therearound, a compression spring, and clutch mechanism comprising a plurality of shoes seated against said friction surfaces, inner and outer wedge followers, said inner wedge being seated against said spring, and a thrust member extending between said followers for each shoe and transmitting thrusts from said followers to said shoe, each of said shoes also having thrust engagement with one of said followers on a plurality of spaced areas along diagonally arranged cylindrical surr faces.

14. In a friction gear, a housing having a flaring open end, a compression spring, and friction means, said friction means comprising inner and outer follower wedges, said inner wedge being seated against saidspring, a plurality of friction shoes symmetrically seated against said flaring open end, thrust means associated with each shoe and having diagonal face engagement therewith and with each of said follower wedges, said inner follower wedge having thrust engagement with each of said shoes on a plurality of spaced diagonal surfaces.

15. In a friction gear, a housing having a flaring open end, a compression spring, friction means, said friction means comprising inner and outer follower wedges, said inner Wedge being seated against said spring, a plurality of friction shoes symmetrically seated against said flaring open end, thrust means associated with each shoe and having diagonal face engagement therewith and with each of said follower wedges, said inner follower wedge having thrust engagement with each of said shoes on a plurality of spaced diagonal arcuate surfaces.

16. In a draft gear, a barrel having a friction end, a compression spring therein, and a clutch mechanism comprising an inner wedge seated on said spring, an outer wedge, shoes seated around said friction end and having diagonal face engagement with said inner Wedge, and thrust members extending between said Wedges and transmitting thrust therefrom to the associated shoes.

1'7. In a draft gear, a barrel having a friction end, a compression spring, and a clutch mechanism comprising an outer wedge, an inner Wedge supported by said spring, a plurality of shoes engaging said friction end and interlocked with said inner wedge, and a plurality of thrust means engaging said Wedges, and the associated shoes, said shoes having diagonal face engagement with one of said wedges.

18. In a draft gear, a barrel having a friction end, a compression spring, and a clutch mechanism comprising an outer wedge, an inner wedge supported by said spring, a plurality of shoes engaging said friction end and interlocked with said inner wedge, and a plurality of thrust means engaging said wedges and the associated shoes, said shoes having diagonal arcuate face engagement with one of said wedges.

RAYMOND C. PIERCE. 

